When ever I try to run this program Eclipse immediately crashes

[nothing5505]

I tried double checking for infinite loops but I can't seem to figure it out. Please help?

 
#include <string>
#include <sstream>
#include <iostream>
using namespace std;
int Snum;
int testScore=0;
struct student{
	string name;
	int idnum;
	int quizAverage;
	string grade;
};
int main() {
	cout<<"How many students are there?";
	cin>>Snum;
	for (int t = 0; t<Snum; t++){
		student s[t];
		cout<<"What is the name of the student";
		getline (cin,s[t].name);
		cout<<"What is their Id number?";
		cin>> s[t].idnum;
			for (int b = 0; b>5; b++){

				cout<<"Please a enter a new test score";
				cin>>testScore;
				s[t].quizAverage = testScore + s[t].quizAverage;
									}
			s[t].quizAverage= s[t].quizAverage/5;
			testScore = 0;
				if (s[t].quizAverage >= 90){
					s[t].grade = "A";
				}
				else if (80<= s[t].quizAverage && s[t].quizAverage < 90){
					s[t].grade = "B";
				}
				else if (70<= s[t].quizAverage && s[t].quizAverage <80){
									s[t].grade = "C";
								}
				else if (60<= s[t].quizAverage && s[t].quizAverage <70){
									s[t].grade = "D";
								}
				else if (s[t].quizAverage <60){
									s[t].grade = "F";
								}

					return 0;

								}
			}

[tpb]

You have a bunch of errors.
And your indentation is insane.

The array s needs to be created before the loop and needs to be of size Snum. (I'll ignore that it's a VLA which are not part of standard C++.)

You're probably going to have some newline woes since you are mixing >> and getline.

quizAverage should probably be a floating point value (double).

See anything wrong here?for (int b = 0; b>5; b++)

The "return 0" should be outside of the loop (just before the very final brace).

[coder777]

You don't have an infinite loop. The program simply crashs.
The origin of the crash is basically line 18. You don't need to create an array. So remove [t] everywhere.

If you want for whatever reason to keep line 18 it needs to be

student s[t + 1]; // Note + 1

otherwise using t as an index would be out of bounds. Arrays in c[++] starts with 0.

[jonnin]

it is not legal to make a run-time array. Some compilers will do it, but its not strictly legal.

so student s[t] where t is not a constant is illegal.
also I think
student s[0] is not allowed, or problematic, and your loop does that, so even a tolerant compiler of the above issue may choke on this one.

you have global variables. These cause problems, try to write it without that.