Evaluating math expression given in character array

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0

So, I have an input expression which is of the form ....?5+8 ...

I need to parse this and evaluate the result. Since I know that the expression starts after the ? and ends with a ' ', I tried this:

int evaluate(char *buffer){
while(buffer[i] != '+' || buffer[i] != '-' || buffer[i] != '*' || buffer[i] != '/'){
    exp[j] = buffer[i];
    i++;
    j++;
}
exp[j] = '\0';
int number1 = atoi(exp);

char operation = buffer[i];
i++;
j = 0;
while(buffer[i] !=' '){
    exp[j] = buffer[i];
    i++;
    j++;    
}
exp[j] = '\0';
int number2 = atoi(exp);

 switch(operation)....
 }

where j is initialized from 0 and i is initialized to the position after ?.

The function is called using evaluate(buffer);

However, I keep getting the error Segmentation Fault (core dumped).

Any Ideas?

asked 44 secs ago

gary

28