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  1. #include <iostream>
  2.  
  3. using namespace std;
  4.  
  5. bool isNumber(string s) {
  6.     if(s.size()==0) return false;
  7.     for(int i=0;i<s.size();i++) {
  8.     	if((s[i]>='0' && s[i]<='9')==false) {
  9.             return false;
  10.         }
  11.     }
  12.     return true;
  13. }
  14.  
  15. int main()
  16. {
  17.    if(isNumber("1243")) {
  18.        cout << "It is a number!";
  19.    }
  20.    else {
  21.        cout << "It is not a number!";
  22.    }
  23.    return 0;
  24. }
Success #stdin #stdout 0s 3456KB
comments (?)
stdin
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Standard input is empty
stdout
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It is not a number!
https://ideone.com/nRX51Y
language:
C++14 (gcc 8.3)
created:
7 years ago
visibility:
public

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