C the operator "?: " how does statement calling part work? [duplicate]

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• What does ? in C mean? 8 answers

On Maxeler machines I am not allowed to use if-else statement so instead, I can only use: condition ? first_expression : second_expression;

On this following code piece, if my condition is false, does the code first run first_expression and than run second_expression. Or does it only run second_expression?

[Q]If it runs first_statement and then second_statement, how can I for code to run only second_statement?

//condition ? first_expression : second_expression;
out[m] =  withinBounds?sum[m]: (<condition>)  ? 
stream.offset(in[m], 0)   :  calculate_sum()  ;

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If I ask this question in a larger picture: If condition_1 is false, does it only run calculate_sum(input_2), without running:

(<condition_2>) ?   stream.offset(in[m], 0)   : 
                     calculate_sum(input)

Second example:

out[m] =  withinBounds?sum[m]:
                    (<condition_1>) ?
                    (<condition_2>) ?   stream.offset(in[m], 0)   : 
                     calculate_sum(input)
                    :calculate_sum(input_2);