Write sequences of instructions for SIC to search a key element in array of 100 words.

Here is a simple sequence of instructions for SIC (Simplified Instructional Computer) to search a key element in an array of 100 words. This is a linear search algorithm, which checks each element of the array one by one.

1. Load the base address of the array into a register. Let's say we use register X for this purpose. The instruction would be LDA ARRAY, where ARRAY is the label for the base address of the array.

2. Load the key element you are searching for into another register. Let's use register A for this. The instruction would be LDA KEY, where KEY is the label for the key element.

3. Initialize a counter to keep track of the number of elements checked. We can use register B for this. The instruction would be LDB #0.

4. Start a loop to check each element of the array. The instruction to start the loop would be LOOP: COMP ARRAY, X.

5. If the element in the array is equal to the key, jump to a label where you handle the found key. The instruction would be JEQ FOUND.

6. If the element in the array is not equal to the key, increment the counter and the array address, and go back to the start of the loop. The instructions would be ADDB #1, ADDX #1, and JUMP LOOP.

7. If the counter is equal to 100, the key is not in the array. Jump to a label where you handle the key not found. The instruction would be JEQ NOTFOUND.

8. The label where you handle the found key would be FOUND: STA RESULT, where RESULT is a label for the location where you want to store the result.

9. The label where you handle the key not found would be NOTFOUND: STA RESULT, where RESULT is a label for the location where you want to store the result.

Please note that this is a simplified version of the instructions and does not include error checking or handling of edge cases. Also, the exact syntax and instruction set may vary depending on the specific version of SIC you are using.