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  1. #include <stdio.h>
  2. #include <math.h>
  3.  
  4. int main(void) {
  5. 	int n;
  6.     scanf("%d",&n); 
  7.  
  8.     double r = fabs(sqrt(8.0 * n + 1)); //um natural n é triangular se e somente se a raiz positiva de sqrt(8n + 1) tabém for um natural.
  9.  
  10.     //Testa se r é um natural
  11.     if(floorf(r) == r)
  12.         printf("SIM, %i EH TRIANGULAR\n", n);
  13.     else
  14.         printf("%i NAO EH TRIANGULAR\n", n);
  15.  
  16.     return 0;
  17. }
  18.  
Success #stdin #stdout 0.01s 5424KB
comments (?)
stdin 
1431
stdout 
SIM, 1431 EH TRIANGULAR
https://ideone.com/r58oyR
language:
C (gcc 8.3)
created:
2 years ago
visibility:
secret

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