c++ check if a string is a number code example

Example 1: c++ is string a number

bool isStringNumber(string str){
for(int i=0;i<str.length();i++){
if(str[i]<'0'||str[i]>'9'){
return false;
}
}
return true; 
}
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Example 2: how to check whether input is string or not

num = input("Enter your number ")

print("\n")
if num.isdigit():
    print("User input is Number ")
else:
    print("User input is string ")