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  1. #include <stdio.h>
  2.  
  3. #define SIZE 100
  4.  
  5. int myStringCompareArray(const char string1[],
  6.                          const char string2[])
  7. {
  8.     int i = 0;
  9.  
  10.     while (string1[i] != '\0' &&
  11.            string2[i] != '\0')
  12.     {
  13.         if (string1[i] < string2[i])
  14.         {
  15.             return -1;
  16.         }
  17.  
  18.         if (string1[i] > string2[i])
  19.         {
  20.             return 1;
  21.         }
  22.  
  23.         ++i;
  24.     }
  25.  
  26.     if (string1[i] == '\0' &&
  27.         string2[i] == '\0')
  28.     {
  29.         return 0;
  30.     }
  31.  
  32.     if (string1[i] == '\0')
  33.     {
  34.         return -1;
  35.     }
  36.  
  37.     return 1;
  38. }
  39.  
  40. int myStringComparePointer(const char *string1,
  41.                            const char *string2)
  42. {
  43.     while (*string1 != '\0' &&
  44.            *string2 != '\0')
  45.     {
  46.         if (*string1 < *string2)
  47.         {
  48.             return -1;
  49.         }
  50.  
  51.         if (*string1 > *string2)
  52.         {
  53.             return 1;
  54.         }
  55.  
  56.         ++string1;
  57.         ++string2;
  58.     }
  59.  
  60.     if (*string1 == '\0' &&
  61.         *string2 == '\0')
  62.     {
  63.         return 0;
  64.     }
  65.  
  66.     if (*string1 == '\0')
  67.     {
  68.         return -1;
  69.     }
  70.  
  71.     return 1;
  72. }
  73.  
  74. int myStringNCompareArray(const char string1[],
  75.                           const char string2[],
  76.                           int number)
  77. {
  78.     for (int i = 0; i < number; ++i)
  79.     {
  80.         if (string1[i] == '\0' ||
  81.             string2[i] == '\0')
  82.         {
  83.             if (string1[i] == string2[i])
  84.             {
  85.                 return 0;
  86.             }
  87.  
  88.             if (string1[i] == '\0')
  89.             {
  90.                 return -1;
  91.             }
  92.  
  93.             return 1;
  94.         }
  95.  
  96.         if (string1[i] < string2[i])
  97.         {
  98.             return -1;
  99.         }
  100.  
  101.         if (string1[i] > string2[i])
  102.         {
  103.             return 1;
  104.         }
  105.     }
  106.  
  107.     return 0;
  108. }
  109.  
  110. int myStringNComparePointer(const char *string1,
  111.                             const char *string2,
  112.                             int number)
  113. {
  114.     for (int i = 0; i < number; ++i)
  115.     {
  116.         if (*string1 == '\0' ||
  117.             *string2 == '\0')
  118.         {
  119.             if (*string1 == *string2)
  120.             {
  121.                 return 0;
  122.             }
  123.  
  124.             if (*string1 == '\0')
  125.             {
  126.                 return -1;
  127.             }
  128.  
  129.             return 1;
  130.         }
  131.  
  132.         if (*string1 < *string2)
  133.         {
  134.             return -1;
  135.         }
  136.  
  137.         if (*string1 > *string2)
  138.         {
  139.             return 1;
  140.         }
  141.  
  142.         ++string1;
  143.         ++string2;
  144.     }
  145.  
  146.     return 0;
  147. }
  148.  
  149. int main(void)
  150. {
  151.     char string1[SIZE];
  152.     char string2[SIZE];
  153.     int number;
  154.  
  155.     printf("Enter the first string: ");
  156.     fgets(string1, SIZE, stdin);
  157.  
  158.     printf("Enter the second string: ");
  159.     fgets(string2, SIZE, stdin);
  160.  
  161.     printf("Enter number of characters to compare: ");
  162.     scanf("%d", &number);
  163.  
  164.     printf("\nUsing array notation:\n");
  165.  
  166.     printf("strcmp result = %d\n",
  167.            myStringCompareArray(string1, string2));
  168.  
  169.     printf("strncmp result = %d\n",
  170.            myStringNCompareArray(string1,
  171.                                   string2,
  172.                                   number));
  173.  
  174.     printf("\nUsing pointer notation:\n");
  175.  
  176.     printf("strcmp result = %d\n",
  177.            myStringComparePointer(string1, string2));
  178.  
  179.     printf("strncmp result = %d\n",
  180.            myStringNComparePointer(string1,
  181.                                    string2,
  182.                                    number));
  183.  
  184.     return 0;
  185. }
Success #stdin #stdout 0s 5328KB
comments (?)
stdin 
Standard input is empty
stdout 
Enter the first string: Enter the second string: Enter number of characters to compare: 
Using array notation:
strcmp result = 1
strncmp result = 0

Using pointer notation:
strcmp result = 1
strncmp result = 0
https://ideone.com/2EWvzn
language:
C (gcc 8.3)
created:
3 hours ago
visibility:
public

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